Toroidal deflection yoke

ABSTRACT

A toroidal deflection yoke comprising a toroidal core, a pair of guide rings mounted on the toroidal core, each guide ring having a plurality of coil isolating partitions formed thereon, and horizontal and vertical deflection coils disposed between these partitions in such a manner that they are isolated from each other.

United States Patent [1 1 Kadota Z7513??? [451 Sept. 11,1973

3,643,192 2/1972 Chiodi 335/213 3,569,881 335/210 TOROIDAL DEFLECTION YOKE lnventor: Tokuzo Kadota, Kyoto, Japan Primary ExaminerGeorge Harris W R Attorney Richard K. Steyens, Robert J. Frank et al.

[22] Filed:

ABSTRACT A toroidal deflection yoke comprising a toroidal core, a pair of guide rings mounted on the toroidal core, each guide ring having a plurality of coil isolating partitions formed thereon, and horizontal and vertical deflection [56] References Cit d coils disposed between these partitions in such a man- UNITED STATES PATENTS net that they are isolated from each other.

3,634,796 1/1972 MiNakanoetpl..............335/213X 'TC'l'iiiin's',"

TOROIDAL DEFLECTION YOKE This invention relates to a deflection yoke for use in the deflection system of cathode-ray tubes and more particularly to the construction of a so-called toroidal deflection yoke in which both the horizontal and vertical deflection coils are mounted on a toroidal core.

Deflection yokes of the saddle type which have been used heretofore have such a construction that horizontal and vertical deflection coils are shaped in the form of a saddle, and after assembling these deflection coils on a frame member of an electrical insulator, a ferrite core is mounted on the assembly. However, the deflection yoke of the saddle type has disadvantages in that it is large in size and complex in construction and requires a large number of copper wires since it must necessarily be provided with externally projecting foldback portions.

In an effort to overcome such a defect, a toroidal deflection yoke has been proposed in which both the horizontal and vertical deflection coils are wound around a toroidal core. While such a toroidal deflection yoke has many advantages including those of compact construction, light weight and less copper wire require-' ments, a winding machine of high precision is required for winding the wires around the toroidal core for the manufacture of the toroidal yoke. Especially, in the case of a deflection yoke for use in a color television receiver, such deflection yoke must have a good convergence characteristic, and in order to meet this requirement, the position and distribution of the windings must be strictly regulated. In a toroidal deflection yoke proposed hitherto in an effort to meet the above requirement, grooved rings are fitted on opposite end portions of a toroidal core for facilitating the accurate positioning of wires. In such a toroidal deflection yoke, however, the precision in the pitch of the grooves on each ring, the precision in the registration of the pitch and phase of the grooves on the opposite rings, the precision of the winding machine and the precision in the positional relationship between the winding machine and the rings must be sufficiently high in order that the wires can be accurately and exactly fitted in the grooves. This means that many difficulties are encountered in the manufacture of such a toroidal deflection yoke. Further, in order to improve the efficiency of the deflection yokeand minimize losses, it is desirable to minimize the power losses in the horizontal and vertical deflection coils, that is, to increase the [JR ratio (inductance to resistance ratio) of the horizontal and vertical deflection coils. However, the number of turns must be increased in order to attain a large L/R ratio. In the deflection yoke in which the grooved rings are used for thewinding of wires, the desired increase in the number of turns may be attained by successively stacking up the wire layers in such a manner that each turn of the wire in the second layer is disposed intermediate between every two adjacent turns of the wire in the first layer, each turn of the wire in the third layer is disposed intermediate between every two adjacent turns of the wire in the second layer, and so on. However, even with such a manner of winding, two or three wire layers are the limit that can be wound in orderly fashion without causing any collapse of the stack, and this imposes a limitation to the number of turns that can be satisfactorily provided. The proposed deflection yoke has thus been defective in that provision of many turns is impossible. Furthermore, in such a superposed winding arrangement, the turns of the wire forming the horizontal deflection coil through which the horizontal deflection current flows are disposed in side-by-side relation with and are superposed on the turns of the wire forming the vertical deflection coil through which the vertical deflection current flows, resulting in an excessive increase in the distributed capacity between the horizontal and vertical deflection coils. Thus, the deflection yoke of the proposed construction has further been defective in that a so-called crosstalk of a considerable degree occurs due to the fact that the horizontal and vertical signals are induced in the vertical and horizontal deflection coils respectively through this distributed capacity.

It is therefore a primary object of the present invention to provide a toroidal deflection yoke which is compact in construction and light in weight, which can be easily manufactured without requiring any highprecision manufacturing steps, which can operate with good efficiency an minimal losses, in which the distributed capacity between the horizontal and vertical deflection coils is quite small, and which has improved convergence and other deflection characteristics.

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front elevation of an embodiment of the toroidal deflection yoke according to the present invention;

FIG. 2 is a section taken on the line I] II in FIG.

FIG. 3 is an enlarged exploded view of guide rings and a toroidal core used in the totoidal deflection yoke;

FIG. 4 is an axial section of the assembly consisting of the guide rings and the toroidal core in the toroidal deflection yoke, the section being shown in reduced scale;

FIG. 5 is a schematic planview, in reduced scale, of one of the guide rings used in the toroidal deflection yoke; I

FIG. 6 is a schematic plan view, in reduced scale, of the other guide ring used in the toroidal deflection yoke;

FIG. 7 is a cross section of another embodiment of the present invention;

FIG. 8 is an axial section of the assembly consisting of the guide rings and the toroidal core in the toroidal deflection yoke shown in FIG. 7, the section being shown in reduced scale;

FIG. 9 is a schematic plan view, in reduced scale, of one of the guide rings used in the toroidal deflection yoke shown in FIG. 7; and

FIG. 10 is a schematic plan view, in reduced scale, of the other guide ring used in the toroidal deflection yoke shown in FIG. 7.

Referring first to FIGS. 1 to 6 illustrating an embodiment of the present invention, a toroidal core 1 of magnetic material such as ferrite is shaped so that it has a large diameter at one end portion 2 thereof and a small diameter at the other end portion 3 thereof. Guide rings 4 and 5 are mounted on the large-diameter end portion 2 and small-diameter end portion 3 respectively. As shown in FIGS. 3, 4 and 5, the guide ring 4 comprises an annular side wall 41 which fits snugly on the outer periphery of the large-diameter end portion 2 of the toroidal core 1, a flange portion 42 extending inwardly from the side wall 41 so as to engage the end face of the large-diameter end portion 2 of the toroidal core 1, and a plurality of equally spaced vane-like partitions 43 projecting radially outwardly from the side wall 41 and axially forwardly from the flange portion 42. The side wall 41, flange portion 42 and partitions 43 are made of an electrical insulator and are molded into an integral unit from, for example, a synthetic resin. As shown in FIGS. 3, 4 and 6, the other guide a ring comprises an annular side wall 51 which fits snugly in the inner periphery of the small-diameter end portion 3 of the toroidal core 1, a flange portion 52 extending outwardly from the side wall 51 so as to engage the end face of the small-diameter end portion 3 of the toroidal core 1, and a plurality of equally spaced vanelike partitions 53 projecting radially inwards from the side wall 51 and axially rearwards from the flange portion 52. The side wall 51, flange portion 52 and partitions 53 are made of an electrical insulator and are moded into an integral unit from, for example, a synthetic resin. The number of partitions 43 of the guide ring 4 is equal to the number of partitions 53 of the guide ring 5. The guide rings 4 and 5 having such a construction are mounted on the opposite end portions 2 I and 3 of the toroidal core 1 as shown in FIG. 4. Then,

as shown in FIGS. 1 and 2, horizontal and vertical deflection coils 6 and 7 are wound around the toroidal core 1 by a winding machine so that they lie in different blocks formed on the toroidal core 1 by the partitions 43 and 53. The manner of winding is such that the segments of the horizontal deflection coils 6 are substantially alternated with the segments of the vertical deflection coils 7. More precisely, except the horizontal and vertical positions, one of the segments of the horizontal deflection coil 6 is disposed in the first block, one of the segments of the vertical deflection coil 7 is disposed in the second block, the next adjacent segment of the horizontal deflection coil 6 is disposed in the third block, and so on.

By virtue of the arrangement above described, the horizontal and vertical deflection coils 6 and 7 are isolated from each other by the partitions 43 and 53 and are toroidally wound around the toroidal core 1 without being superposed on each other. The toroidal deflection yoke thus obtained is compact in construction and light in weightand requires a small number of copper wires compared with the conventional deflection yoke of the saddle type. Further, the wire may merely be wound in the individual blocks defined between the partitions 43 and 53during the winding operation with this manner of winding, the coil portions in the individual blocks are confined within the areas between the partitions 43 and 53, thereby attaining the same effect as when the width of the groove provided for each coil turn in the conventional deflection yoke is enlarged to a greater width. Thus, the toroidal deflection yoke according to the present invention is advantageous in that extremely high precision is not required in the manufacturing process including the winding step and the yoke can be very easily manufactured. Furthermore, due to the fact that the horizontal and vertical deflection coils 6 and 7 are isolated from each other by the partitions 43 and 53, the breakdown voltage characteristic of the horizontal and vertical deflection coils 6 and 7 can be greatly improved compared with the conventional arrangement including the superposed layers of the horizontal and vertical deflection coils, and at the same time, due to the reduced contact areas between the horizontal and vertical deflection coils 6 and 7, the distributed capacity therebetween can be reduced to a very small value thereby substantially eliminating undersirable crosstalk. In the toroidal deflection yoke according to the present invention, the partitions 43 and 53 may have sufficient height so that the number of turns in each block can be increased without giving rise to any collapse of the stacked wire turns. This is advantageous in that the inductance of the horizontal and vertical deflection coils 6 and 7 can be increased without adversely affecting the magnetic field distribution, thereby increasing the L/R ratio, improving the deflection efficiency and minimizing the undesireble losses. Moreover, due to the fact that the horizontal and vertical deflection coils 6 and 7 are divided into a plurality of coil portions to be disposed in the individual blocks, the number of turns in the individual blocks may be suitably selected so as to carefully distribute the winding to control the magnetic field distribution thereby obtaining a toroidal deflection yoke having any desired characteristic. Furthermore, due to the fact that the horizontal and vertical deflection coils 6 and 7 are disposed in different blocks, the coil characteristic and the number of turns can be easily regulated independently of each other without applying any change to the other, thereby obtaining a toroidal deflection yoke having a very satisfactory convergence characteristic.

In the embodiment above described, the height of the partitions 43 and 53 is necessarily such that it is at least larger than the height of the segments of the horizontal and vertical deflection coils 6 and 7 in the individual blocks. This is required in order that the wire in the uppermost layer in each block may not project beyond the end face of the partitions 43 and 53 defining such a block, and this provides, at the same time, the following advantages. Namely, it is necessary to support the assembly consisting of the toroidal core 1 and the guide rings 4 and 5 on a winding machine during winding of the wire into the horizontal and vertical deflection coils 6 and 7. During the winding operation on the winding machine, the assembly may be supported on the machine by clamping or otherwise holding the end portions of the partitions 43 and 53 so as to avoid direct contact of the wire with the machine while the assembly is supported on the machine and while it is mounted on and dismounted from the machine, thereby eliminating damage to the wire. During the winding operation, the toroidal core 1 must be supported on the machine in such a manner that its axis is always maintained in the predetermined position. In the present invention, the toroidal core 1 can be supported in such a position by clamping the partitions 43 and 53 which are always maintained in the fixed dimensional position throughout the wire winding operation until the horizontal and vertical deflection coils 6 and 7 are completely formed. The toroidal core 1 can be accurately supported in the predetermined axial position throughout the winding operation, and the prior defect can be eliminated in which the axis of the toroidal core is gradually displaced as the wire is successively wound.

In the embodiment having a construction as above described, the horizontal and vertical deflection coils 6 and 7 may be wound in such a manner that they have maximum turns in the central block and successively smaller turns toward the end blocks so that their winding distribution is analogous to the so-called cosine distribution. This manner of winding provides the advantage in that a more uniform magnetic field distribution can thereby be obtained.

Another embodiment of the present invention will next be described with reference to FIGS. 7 to 10. This embodiment is generally similar to the first embodiment in that a guide ring 14 comprising a side wall 141, a flange portion 142 and a plurality of partitions 143 is fitted on a large-diameter end portion 12 of a toroidal core 11, while another guide ring comprising a side wall 151, a flange portion 152 and a plurality of partitions 153 is fitted in a small-diameter end portion 13 of the toroidal core 1 l, and horizontal and vertical deflection coils l6 and 17 are alternately disposed in different blocks defined by these partiions 143 and 153. The second embodiment differs from the first embodiment in that the partitions 143 and 153 on the respective guide rings 14 and 15 are spaced apart by a maximum distance at a portion corresponding to the central portion of the horizontal and vertical deflection coils 16 and 17 and this spacing becomes successively narrower toward the end portions of the deflection coils l6 and 17.

By virtue of the above arrangement, a winding distribution analogous to the so-called cosine distribution can be easily obtained even when the wire is wound in such a manner as to provide the horizontal and vertical deflection coils l6 and 17 of substantially the same height throughout the entire circumference of the toroidal core 11. The toroidal deflection yoke formed in this manner is advantageous in that it has a uniform magnetic field distribution. It will be understood-that this toroidal deflection yoke possesses all the advantages possessed by the first embodiment.

While two embodiments of a toroidal deflection yoke in which block-forming means such as a pair of guide rings having a plurality of vane-like partitions of short axial length are fitted to the opposite end portions of a toroidal core have been illustrated by way of example, the present invention is in no way limited to the specific embodiments above described, and it is apparent that such guide rings may have a plurality of partitions which extendover the substantial portions of or the entire surface of the toroidal core. It will be readily understood that the advantages above described become more marked when the guide rings have partitions which extend over the entire surface of the toroidal core.

What is claimed is: i

l. A toroidal deflection yoke, comprising: an annular core of a magnetic material; deflection coil guide means provided at the opposite ends of said annular coil and having a plurality of bladeshaped partitions extending radially and longitudinally of said annular core, said partitions dividing said core into a plurality of blocks; and a plurality of deflection coil portions, each portion comprising a plurality of turns wound in a corresponding one of said blocks, said partitions having a height larger than the full height of the plurality of turns of each coil portion would in the block form by adjacent partitions. 2. A toroidal deflection yoke as claimed in claim 6, in which said guide means comprises two annular guide rings, one disposed at each end of said annular core and each having a plurality of said blade-shaped partitions extending radially and longitudinally of the annular core so as to divide the outer periphery of said annular core into a plurality of blocks.

3. A toroidal deflection yoke as claimed in claim 6, in which said plurality of partitions provided on each of said guide means are equally spaced from each other.

4. The toroidal deflection yoke defined in claim 1, wherein said deflection coil portions comprise respective portions of horizontal and vertical deflection coils for an electron beam tube, and wherein the spacing between adjacent blade-shaped partitions between which one coil portion of one of said horizontal and vertical deflection coils is wound decreases from a maximum at the location of the coil portion forming the center of said one of said horizontal and vertical deflection coils to a minimum at the furthest circumferentially distant ends of said one coil from said center.

5 The toroidal deflection yoke defined in claim 4, wherein the coil portions forming said horizontal deflection coil are wound in said blocks in alternating relation with the portions forming said vertical deflection coil.

6. The toroidal deflection yoke defined in claim 5, wherein the height of all of said coil portions in their respective blocks is substantially the same around the circumference of said annular core, the winding distribution being in the form of a cosine distribution.

7. The toroidal deflection yoke defined in claim 6, wherein said deflection coil portions comprise respective portions of horizontal and vertical deflection coils for an electron beam tube and wherein the coil portions forming said horizontal deflection coil are wound in saidtblocks in alternating relation with coil portions forming said vertical deflection coil. 

1. A toroidal deflection yoke, comprising: an annular core of a magnetic material; deflection coil guide means provided at the opposite ends of said annular coil and having a plurality of blade-shaped partitions extending radially and longitudinally of said annular core, said partitions dividing said core into a plurality of blocks; and a plurality of deflection coil portions, each portion comprising a plurality of turns wound in a corresponding one of said blocks, said partitions having a height larger than the full height of the plurality of turns of each coil portion would in the block form by adjacent partitions.
 2. A toroidal deflection yoke as claimed in claim 6, in which said guide means comprises two annular guide rings, one disposed at each end of said annular core and each having a plurality of said blade-shaped partitions extending radially and longitudinally of the annular core so as to divide the outer periphery of said annular core into a plurality of blocks.
 3. A toroidal deflection yoke as claimed in claim 6, in which said plurality of partitions provided on each of said guide means are equally spaced from each other.
 4. The toroidal deflection yoke defined in claim 1, wherein said deflection coil portions comprise respective portions of horizontal and vertical deflection coils for an electron beam tube, and wherein the spacing between adjacent blade-shaped partitions between which one coil portion of one of said horizontal and vertical deflection coils is wound decreases from a maximum at the location of the coil portion forming the center of said one of said horizontal and vertical deflection coils to a minimum at the furthest circumferentially distant ends of said one coil from said center.
 5. The toroidal deflection yoke defined in claim 4, wherein the coil portions forming said horizontal deflection coil are wound in said blocks in alternating relation with the portions forming said vertical deflection coil.
 6. The toroidal deflection yoke defined in claim 5, wherein the height of all of said coil portions in their respective blocks is substantially the same around the circumference of said annular core, the winding distribution being in the form of a cosine distribution.
 7. The toroidal deflection yoke defined in claim 6, wherein said deflection coil portions comprise respective portions of horizontal and vertical deflection coils for an electron beam tube and wherein the coil portions forming said horizontal deflection coil are wound in said blocks in alternating relation with coil portions forming said vertical dEflection coil. 